Commercially-available liquid toilet bowl cleaning compositions generally incorporate mineral acids such as hydrochloric, sulfuric or phosphoric acid. A typical product might contain about 5-35% hydrochloric acid. In response to the danger associated with such liquid acid compositions, such as spillage onto substrates other than those intended for cleaning, skin burns or irritation, deleterious effects upon metals, accidental ingestion and the like, bowl cleaning compositions formulated as mixtures of solids were developed. These compositions incorporated acidic active ingredients such as sodium bisulfate, sulfamic acid, oxalic acid or citric acid in combination with surfactants, disinfectants, dyes and perfumes. Solid compositions are considered to be safer to use. However, solid toilet bowl cleaning compositions present the problem of over- or underuse due to measuring difficulties.
In an attempt to overcome these difficulties, acidic bowl cleaning compositions have been provided in unit application water-soluble pouches or envelopes. An envelope of the composition would be introduced into the bowl water and the resultant solution spread around the inner bowl surfaces with a bowl mop, often after allowing the cleaning composition to stand in the water without agitation. Manual agitation of the dissolved cleaning chemicals has heretofore been the primary means used to remove the ring of scale which forms predominantly at or slightly above the bowl water level, and which consists primarily of rust, grease and deposited salts.
Therefore, it is an object of the present invention to provide a toilet bowl cleaner which is self-starting, that is, which agitates and/or foams the bowl water upon dissolution therein, thereby wetting and aiding the removal of scale deposits located above the water line of the bowl.
It is another object of the present invention to provide a toilet bowl cleaner comprising a packaged, self-neutralizing composition, that is, one which is formulated and packaged so that the acidic component is neutralized after the period in which it performs its cleaning function, thus rendering the bowl contents non-toxic and non-corrosive.
It is yet another object of the present invention to provide a toilet bowl cleaner comprising a self-neutralizing composition which indicates when it is in the acidic state and when it is in the neutral or basic state.
Other objects, advantages and novel features of the present invention will be apparent to those skilled in the art from the following description and appended claims.